Harry said of the children he met on his three-day visit to Lesotho: “Their resilience is astounding and makes me feel extremely humble.

“It makes me more determined than ever that these wonderful, awe-inspiring children should have happier and healthier lives.”

He added: "I have met some of the children who have attended the Mamohato Camps, and they have so much more confidence and knowledge of how to live healthy lives.

"With the new Mamohato Camp we will be able to reach four times as many children each year.

"It will also be the centre for training new staff and volunteers for our expansion in southern Africa."

The Prince, who used public transport to travel from the airport into Johannesburg earlier, on South Africa's new Gautrain service, added: "The programme encourages children to talk to one another, to learn about the disease, and spread word of their learning through a safe support network.

"Talking about HIV and understanding it isn't dangerous. Denying it, or not knowing about it, definitely is."